Phonon lifetimes in bulk AlN and their temperature dependence

We report on the Raman analysis of the phonon lifetimes of the A(1)(LO) (longitudinal optical) and E-2(high) phonons in bulk AlN crystals and their temperature dependence from 10 to 1275 K. Our experimental results show that amongst the various possible decay channels, the A(1)(LO) phonons decay primarily into two phonons of equal energy (Klemens model), most likely longitudinal-acoustic phonons, whereas the E-2(high) phonon decays asymmetrically into a high-energy and a low-energy phonon. Possible decay channels of the E-2(high) phonon have been shown to include combinations of E-2(low) and acoustic phonons. Phonon lifetimes of the A(1)(LO) phonon and the E-2(high) phonon of 0.75 and 2.9 ps, respectively, were measured at 10 K. (C) 2000 American Institute of Physics. [S0003-6951(00)00339-9].